<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/113272>113272</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] Complex multiplications are not correctly rounded. 
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          Sh0g0-1758
      </td>
    </tr>
</table>

<pre>
    Refer this report : https://inria.hal.science/hal-04714173, which hints towars the issue in CMPLX FP multiplication. 

This can be observed in the following example in which I compare the results from GNU MPC (infinite precision) with the results from clang (trunk) and gcc (trunk) for 32 bit precision. 

```
a (GNU MPC)         = 0x1.9387bep+0 + 0x1.485eb4p+1*i
a (clang and gcc)   = 0x1.9387bep+0 + 0x1.485eb4p+1*i
b (GNU MPC)         = -0x1.8bee4ep+1 + 0x1.039aep+2*i
b (clang and gcc)   = -0x1.8bee4ep+1 + 0x1.039aep+2*i

(a * b) (GNU MPC)   = -0x1.e904f'e'p+3 + -0x1.8a95'4e'p+0*i
(a * b) (gcc -O3)   = -0x1.e904f'e'p+3 + -0x1.8a95'58'p+0*i
(a * b) (clang -O3) = -0x1.e904f'c'p+3 + -0x1.8a95'58'p+0*i
(a * b) (clang):    = -0x1.e904f'c'p+3 + -0x1.8a95'58'p+0*i
(a * b) (gcc):      = -0x1.e904f'c'p+3 + -0x1.8a95'58'p+0*i
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJyslF9v5CYUxT8NfrkaC-M_2A9-mCSaqlK3jfpH6ivga5uWAQtwkv32Fbazu5ltq0bb0QjL15zfPYA4IgQ9WcSe1HekfsjEGmfn-19mOtFTwes2k2742P-MI3qIsw7gcXE-AinPMMe4BFKeCbsQdtHWa5HPwuRBabQKCbvMwpxoxYuq4CVh9_A8azXDrG0MEN2z8AHijKBDWBG0hfsPjz_8DpdHuK4m6sVoJaJ2NgdCHwg97-OvyYYSFiSCkwH9Ew5JnEijM8Y9azsBvojrYjbq3vV7UO66CI_bRI9hNTHA6N0VvvvxN_jweA-EtdqO2uqIsHhUOmhnCevgWcf5a5kywk5JFP1q_0zzhB1gUupNbXQeSgZSx8_MtwsiDT3-26tI8sNSArz-SPkA9KXIu7LlEhfC7igQdrfVqrZGWaVaQdhZfwHaTR7Gdty7QfJfHJ2SqpWI1UYqPpFo2YmtxG5A_-DoXaBjZG1a4xlkwtx6_ATFjlYjYRwJ44lTbui9n-hqwnj1-ol-0eIWng729FP5bnjd_gf4vikH_iu4-h_ghHXp0v6d92_E78d4wL8d_3obsqEvh67sRIZ9wVlX8443TTb3XGLTiZI3I8ehHNumqOtaVlzJqsGW00z3jLKqoIzRpupYk5dDx7Go5IgDr4VkpKJ4Fdrkxjxdc-enbIugvihKxllmhEQTtkxk7Ng8luLR90lwkusUSEWNDjF8RkQdzRaku6J-gHuXIujlJs0CpBCyLoJy3qOK5iN4t9oBhxyy1Zv-bbBOOs6rzJW7EnZJ3Y7HafHuD1QxZW9yHwi7HAt46tlfAQAA__8pTpwL">